title: The in vitro effects of nicotine and cotinine on prostacyclin and thromboxane biosynthesis.
abstract: The comparative effects of nicotine and cotinine on the biosynthesis of prostacyclin (PGI2) and thromboxane A2 (TXA2) in the horse aorta and platelet microsomes were studied. TXB2 and 6-keto PGF1a stable metabolites of TXA2 and PGI2 respectively were determined by radioimmunoassay. TXA2 production in the presence of either nicotine or cotinine treatment was not altered. However, a dose dependent inhibition of PGI2 biosynthesis, and a dose dependent stimulation of PGI2 biosynthesis, was observed in the presence of nicotine and cotinine respectively. Moreover, cotinine (10b3 M) was able to prevent the inhibitory effect of nicotine on PGI2 synthetase when preincubated with horse aorta microsomes. It appears that cotinine, the major nicotine metabolite resulting from a breakdown process, could be useful for the organism, at least for the cardiovascular system.
authors.affiliation: Centre de recherche, Hôpital du sacré coeur de Montréal, Québec, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Chahine
authors.forename: A
authors.initials: A
authors.lastname: Calderone
authors.forename: C
authors.initials: C
authors.lastname: Navarro-Delmasure
mesh_terms: D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000378:metabolism; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism; D003367:Cotinine / Q000494:pharmacology*; D011464:Epoprostenol / Q000096:biosynthesis*; D006736:Horses; D066298:In Vitro Techniques; D007700:Kinetics; D008861:Microsomes / Q000187:drug effects / Q000378:metabolism; D009538:Nicotine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D013928:Thromboxane A2 / Q000096:biosynthesis*
chemical_list: D013928:Thromboxane A2; D009538:Nicotine; D011464:Epoprostenol; D003367:Cotinine